1. Field of the Disclosure
This disclosure generally relates to an electronic device and, more particularly, to an electronic device capable of improving the electrostatic protection ability of the optoelectronic device and the utilization of the substrate area.
2. Description of the Related Art
The optical mouse generally includes an image sensor package which has the function of emitting light and sensing light. For example, FIG. 1 is a schematic diagram of an image sensor package 92 and a circuit board 90 included in a conventional optical mouse. The image sensor package 92 includes a light emitting diode 922, an image sensor 924 and a plurality of connecting pins 926. The circuit board 90 includes a plurality of metallized holes 902 and a circuit board opening 904, wherein the circuit board opening 904 is for the transmission of light therethrough. The image sensor package 92 is combined with the circuit board 90 by inserting the connecting pins 926 into the metallized holes 902 respectively.
When the optical mouse is put on a working surface, light emitted from the light emitting diode 922 passes through the circuit board opening 904 to illuminate the working surface, and the image sensor 924 receives reflected light from the working surface also through the circuit board opening 904.
In this structure, as the image sensor package 92 and the light emitting diode 922 send and receive signals via the connecting pins 926, the image sensor package 92 can be damaged when the electrostatic discharge (ESD) occurs on the connecting pins 926.
For example, FIG. 2 is a cross-sectional view along line 2-2′ of the image sensor package 92 of FIG. 1 as well as a housing 94. When the image sensor package 92 is mounted on the circuit board 90 and integrated in the optical mouse, in order to allow the image sensor package 92 to efficiently capture images, a lens 96 is disposed between the image sensor package 92 and the housing 94 such that free ends of the connecting pins 926 are separated from the housing 94 by a distance h. In order to decrease the influence of the electrostatic discharge, a large lens can be adopted so as to increase the distance h thereby increasing a discharge path. However, using a large lens can increase the manufacturing material of the lens thereby increasing the cost.
In addition, as the circuit board 90 has the circuit board opening 904, the electrical traces on the circuit board 90 can only be laid on the rest substrate surface such that the utilization of the substrate area is degraded.